Wave Pitch Analysis via Vessel Motion Correlation
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Solution Overview
Problem
Current methods for determining sea state variables, such as those used by free-floating wave buoys and vessel radars, are limited in accuracy and reliability, especially in adverse weather conditions, and fail to account for rotational movements and the specific stability factors affecting watercraft.
Innovation Solution
A method that records time profiles of movement variables like yaw angle, roll angle, heave speed, and pitch angle speed on a watercraft to determine sea state variables independently of weather, using correlation values to quantify temporal relationships and filter out non-influential wave components, allowing for accurate and reliable determination of wave direction and period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vessel radar equipment is used to detect sea state, then sea state variables can be determined at the vessel's location, but the signal quality deteriorates in heavy rain or snowfall and the installation becomes expensive and time-consuming
Solution Approach 1:
The patent replaces radar-based electromagnetic detection with a mechanical motion analysis approach. By using motion sensors (accelerometers, gyroscopes) to measure the vessel's actual physical movements and analyzing these mechanical responses through correlation methods, the system determines sea state variables without relying on radar signals that are compromised by precipitation.
2Reliability
If free-floating wave buoys are used to measure sea state variables, then measurements are weather-independent, but they only record data at a few locations and cannot provide comprehensive information about sea state variables affecting vessel stability
Solution Approach 1:
The vessel itself serves as the measurement platform. By utilizing the vessel's own motion sensors to record its responses to wave forces, the system eliminates the need for separate buoy-based measurement systems. This self-measurement approach provides comprehensive data about the sea state variables that actually affect this specific vessel's stability, combining weather independence with location-specific relevance.
3Measurement precision
If wave height measurement is performed using known methods, then sea state variables can be obtained, but the measurements are influenced by heavy rainfall and other weather conditions
Solution Approach 1:
The patent replaces direct wave height measurement (which is susceptible to weather interference) with indirect inference through motion analysis. By measuring the vessel's acceleration, velocity, and angular movements caused by wave forces and analyzing the temporal correlations between these motion parameters, the system derives wave characteristics without directly observing the waves, thereby eliminating precipitation and weather conditions from the measurement process.
Data Source
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AI summary
The method involves capturing the waveforms of two movement variables of a vessel. A correlation value is determined from a pair of time courses and one or multiple swell sizes. The wave form is detected by three movement variables of the vessel. Multiple pairs of temporal sequences are determined by a correlation value. A correlation function is used as multiple correlation values in a pair of temporal sequences.